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Poster: FP   Date: Jan 31, 2010 1:13pm
Forum: feature_films Subject: VIDEO CELLAR movies

First, special thanks for these unique and sometimes weird additions. They're lots of fun.

A problem, however: Interlace artifacts. Upon examining still frames, any motion is often represented by a double-framed smear. This suggests something has gone awry between source and encoding.

G-Spot says the videos are 25 fps, with vertical pixel resolutions all over the map, which prevents properly interlaced files. This suggests the encodes were done somewhere other than the US or Japan, perhaps by someone using the PAL standard. Depending on program source and encoding software, these doubled frames can result. It's hard to say for sure, but these files look almost as if they originated as 29.97, pulled-down NTSC videos that were transcoded to 25fps PAL progressive, at random resolutions, without allowing for frame rate correction.

Most of the Prelinger offerings (at least the older ones) are 480 vertical lines, 3:2 pulldown interlaced 29.97 fps files made from 24 fps originals. These clean encodes allow the fields to be reconstructed in After Effects to recreate the 24 fps cadence, allowing each frame to be cleanly extracted for further processing.

Unfortunately, many recent archive.org uploads such as some or all Video Cellar contributions, have full-frame combined-field artifacts that are essentially impossible to remove. This makes re-purposing the files far more difficult.

Just a suggestion of something to watch out for - - -

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Poster: Video-Cellar Date: Jan 31, 2010 3:26pm
Forum: feature_films Subject: Re: VIDEO CELLAR movies

With a few exceptions, the material I am uploading has been mastered in PAL system. Some were transferred from film using a PAL variant of the 3:2 method (every 12th frame is held for a 3rd field [no slow down or speed up of the 24frames/sec, but sometimes a noticable judder]). It is hard to find places that will do 3:2 PAL anymore so most are marked up to 25frames/sec and spread over the 50 interlaced fields. It's likely that a few of the items I have collected from outside tape libraries could have originated as NTSC masters, but this is difficult to confirm for sure.

Some of the more unusual stuff I am uploading is coming form VHS dupes because I have either sold, can't find or can't use the master tape (I have a few U-Matic tapes and no machine at the moment).

I encode the original tapes to Interlaced PAL Mpeg2 before creating MP4 file. I think the root of the problem you have been seeing could be that, by default, my encoder has been de-interlacing when creating the MP4 videos. I'll have a go at keeping the original interlacing when creating the MP4 file and see if that fixes the problem.

I am also attempting to get the highest capture resolution I can, so that the MP4s are made from the best quality master file. Its a new collection and I am trying to iron out all the wrinkles. I want the files to be as useful and usable as possible.

This post was modified by Video-Cellar on 2010-01-31 23:26:02

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Poster: FP   Date: Feb 1, 2010 11:19am
Forum: feature_films Subject: Re: VIDEO CELLAR movies

Thanks for that! I apologize if my post came off as "bitching about free", which it was, essentially. Your films are a breath of fresh air, especially considering the curators of the archive have yet to return from their collective walkabout, and there have been no other major uploads of ephemeral films for over a year.

I'm so used to re-purposing PD content from archive.org, I get a little "spoiled" when everything isn't just right. Uncool of me...